[whatwg] First or last Content-Type header?

Julian Reschke julian.reschke at gmx.de
Tue Jun 2 01:31:00 PDT 2009


Adam Barth wrote:
> Sure.  For the sake of discussion, let's say IE6 and IE7.  Basically,
> if the Content-Type header contains a value IE knows about, then IE
> pretty much ignores the value and engages its sniffing algorithm.  So,
> for example, if a response has:
> 
> Content-Type: text/html
> Content-Type: image/gif
> 
> and is really a GIF.  IE will show the image correctly because it will
> see the text/html type, ignore it, and then sniff GIF from the
> content.  By contrast, Firefox and Chrome will see the type image/gif
> type and show the image correctly.  This is quite likely to occur on
> the web because it works in every browser.
> 
> Now, consider the reverse:
> 
> Content-Type: image/gif
> Content-Type: text/html
> 
> In this case, IE renders the image correctly, but Firefox and Chrome
> don't show the image.  This is less likely to occur on the web because
> it doesn't work in Firefox (e.g., >20% of the market).

Thanks!

BR, Julian



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